Typing text that uses non-Roman alphabet characters has always been far more cumbersome than it could be, very often preventing the native speakers of languages that use non-Roman script from using their native languages in writing.
There are various reasons that make typing text in non-Roman characters unpopular. For example, an input method for inputting non-Roman script is not readily available. Typically a user must install a special keyboard or software for inputting non-Roman script. Even after such a keyboard and software installation, a user must learn which keys correspond to which characters in order to use it. This requires too much effort for casual users to type in their native script. It also causes many non-Roman script languages to be written in the Roman alphabet.
Another reason that typing in non-Roman text is not popular is that the accuracy of most input methods is not sufficient. For Chinese and Japanese, phonetic input has virtually been the sole method for inputting over 5,000 characters. In a phonetic input method, a user types in the characters as they are pronounced; these pronunciations are then converted into desired characters. Note that the conversion is by no means trivial, because the phonetic sequence is highly ambiguous. The best conversion depends on the context, domain, and ultimately on the user.